This application requests five years of funding for the Population Research Institute (PR!) at The Pennsylvania State University. PRI is a vibrant, multidisciplinary center that provides strategic resources in support of innovation and excellence in population research. PRI has 66 faculty associates/affiliates from 14 departments and 5 colleges. The center emphasizes research in four major signature themes: (1) immigration and immigrant adaptation; (2) American neighborhoods and communities; (3) health and well-being in adolescence and young adulthood; and (4) health disparities. Research within these themes is facilitated by the activities and services of five research infrastructure cores: (1) Administrative Core, (2) Computer Core, (3) Data, Programming and Statistics Core, (4) Geographic Information Analysis Core, and (5) Developmental Infrastructure Core. These cores provide many cost-effective services to PRI researchers that are not ordinarily available to Penn State University faculty. The center also provides forums for learning and exchange (working groups, a speaker series, workshops, and symposia), project development assistance, and seed funding. PRI effectively leverages resources from within Penn State to build interdisciplinary expertise in population science, to invest in promising research directions, and to enhance its infrastructure. PRI is distinctive in at least three important respects. First, it is a well-established center with strong roots in core areas of population science, yet it enriches research in those areas by integrating perspectives and methodologies from human development, biology, and geography. Second, PRI is changing with the times. It is a leader in new areas of research and research methodology, and its infrastructure is responsive to emerging research opportunities and challenges. In addition, the center invests in the career development of promising young population scholars who are recruited to Penn State. Third, PRI faculty associates are uniformly highly productive and nearly all are grant active; this strength cuts across all levels of seniority.